“The inspiration really came from my producer friend Michael Mills of Mills Entertainment,” says Jim Millan, the director and head writer of “Spank! The Fifty Shades Parody” from his home in Toronto. “They had a lot of success with ‘Potted Potter [The Unauthorized Harry Experience’]. They asked the question, ‘Is there anything else in pop culture that would be a fun target for a parody show?’ Someone suggested ’50 Shades of Grey’ and all of the women in the office said, ‘Yes, Yes!’ “

Millan, who has worked with sketch comedy troupe Kids in the Hall, came on board in August. “My wife and I were in the Rocky Mountains at the time,” he explains. “I told her I had to read this book ‘50 Shades of Grey’. I assure you I was the only man anywhere in the Rocky Mountain range reading that book. Six weeks later we were in front of an audience of screaming women.”

The path from book page to musical stage was a little different for "50 Shades! The Musical," according to the show’s writer and director Al Samuels, a Los Angeles-based actor/writer who co-founded the Baby Wants Comedy improv troupe in his hometown of Chicago.

"The Edinburgh Fringe Festival asked [Baby Wants Comedy], 'Would you put together a parody of the '50 Shades of Grey' book?' We said, 'Absolutely.' If you're going to do improv then you have to really be up on pop culture and all that junk stuff in the world. Well, I love it. I love 'Twilight.' I love 'Harry Potter.' I love '50 Shades.' There is such a rich world there to poke some fun with, both in the book and the phenomenon around the book."

They scripted a one-act and rehearsed it practically overnight in July 2012. "It killed," says Samuels. "We sold out and we got great press." So they brought the show home to Chicago, tinkered with it, and opened it off-Broadway in January.

Both shows are musicals. "Some of the songs have elements of a sketch show or a burlesque show or something you'd see on 'Saturday Night Live,' " Millan says of "Spank," which uses recorded orchestrations. "Others are straight-up musical numbers. We do parody of pop songs and Broadway songs."

On the other hand, Samuels says "50 Shades" has a live trio band and original songs. "That is where the improv years and years of musical theater really help. In our story of Anna and Christian, Anna is this 21-year-old virgin working hard in a hardware store. In the beginning of the story there is something missing in her life. She begins to sing, 'I wish there was something big to fill this hole in me,' which is ... not only a double entendre, but also a big heartfelt emotion."